I was really planning on getting a million miles from my cummins, but yesterday, with only 436,000 miles on it, I jackknifed hauling a gooseneck trailer, while sliding downhill on ice: the gooseneck swang so far around that it dented the drivers side upper rear corner of the cab (close to my head), bending drivers door and shattering drivers side window; bending rear wall of cab (sliding rear window just fell out of it), and bending roof down in that corner. I shifted to 4x4 on the fly while sliding, and, though damaged, was able to straighten out, and drive it home. Except for the snow blowing through the inside of the cab, it still drove great. It's a work horse, and pulls three separate trailers for us, all gooseneck. Is it easier to just drop the drivetrain, and install in another shell, or can just the cab of the truck be swapped. Can the door, roof, and rear wall of the cab be replaced separately?